1. Field of the Invention
The present invention relates to a portable circular saw and more particularly, to a technique of performing a bevel cutting operation with a saw blade held inclined to a workpiece.
2. Description of the Related Art
A known portable circular saw having a bevel cutting mechanism is disclosed in U.S. Pat. No. 6,202,311. In the known circular saw, a bevel angle of a circular saw body to a base can be adjusted to any angle within a range between a minimum angle or 0° at which the blade is at right angles to the base and a maximum angle (for example, about 50°). In addition, a restricting arrangement is provided to temporarily secure the bevel angle of the circular saw body to common bevel angles of e.g. 45° that are frequently selected by an user of the circular saw for cutting operation. With this restricting arrangement, the circular saw body can be readily secured to a common bevel angle.
The known restricting arrangement is configured such that a spring biased ball formed on a circular saw body-side member is engaged in a spherical recess formed on a base side member and thereby restricts the bevel angle of the circular saw body to a common bevel angle. Therefore, the user of the circular saw may freely select and fix the desired bevel angle without respect to the common bevel angle, while the user may use the common bevel angle which is automatically set via an engagement of the ball and the recess of the restricting arrangement. On the other hand, due to providing such automatically settable common bevel angle, fine adjustment of the bevel angle in the vicinity of the common bevel angle is quite difficult because in such region close to the common bevel angle, the ball tends to engage with the recess and may hinder the fine adjustment of the bevel angle.